Concentrator



Jan. 25, 1938. A. c. MUNRO 2,106,155

CONCENTRATOR Filed July l, 1936 5 Sheets-Sheet l f n'n-Tm A TT ORNEYS.

Jan. 25 1938.

A. C. MUNRO CONCENTRATOR Filed July 1,- 193e 5 sheets-sheet 2 2 v51/filo Jan. 25, 1938. A. c. MUNRo CONGENTRATOR Filed July .1, 1936 5 Sheets-Sheet 3 INVENTOR. `lexa/zoezwGJVISLUZP@ BY M M/ ATTORNEYS.

Jan. 25,1938. A. C. MUNRO I 2,106,155

GONCENTRATOR Filed July l, 1936l 5 Sheets-'Sheet4 4 Patented Jan. 2 5, 1938 PATENT OFFICE coNcENTnATon Alexander C. Munro, Britannia Beach, British Columbia, Canada.

Application July 1:1936, Serial No. 88,398

7 Claims.

This invention relates to an ore concentrating apparatus and pertains particularly to a combined classifying and flotation apparatus useful in the recovery of minerals or the like by froth flotation.

This application is a continuation-impart of my two co-pending applications, Serial Nos. 15,041, led April 6, 1935, and 22,503, filed May 21, 1935.

The principal object of the invention is to provide an apparatus of the character described having a low installation cost, long life, a low up-keep cost, and a lower power consumption than commercially available forms of apparatus of comparable utility.

A further object of the invention is to provide an apparatus provided with aerating agitator means and adapted to function as a classifying apparatus wherein certain described. aeration features are obtained co-incidentally and in cooperation with a classifying operation.

A further object of the invention is to provide an apparatus in which an ore pulp or the like, comprising a liquid suspension containing mixed relatively coarse and relatively fine solid particles, together with solid mineral particles which are separable by froth flotation, is subjected to both froth flotation and classifying operations in a single tank, and in which a froth fiotation concentrate, a setled coarse fraction, and a fine slimes fraction. are separated from said pulp and separately discharged from said tank.

A further object of the invention is to provide means for subjecting a fluid body containing, in suspension, divided mineral particles of a floatable nature and particle size range together with fine particles which are not susceptible to froth flotation and also relatively coarse particles which may contain mineral values but which are not susceptible to, froth dotation Without further size reduction, to an aerating agitation in the production of a froth concentrate containing the principal portion of mineral values of a floatable size, land means co-operating with said agitating means to effect a classifying opera'- tion on the unfioated material to recover therefrom suchrelatively coarse particles and to discharge such coarse particles as a. separate product and at a. point removed from the discharge cf residual fine solids or slimes in suspension.

Other objects and features of the invention will be brought out in the following description of preferred embodiments thereof, or will be apparent from such description.

The vdevice of the present invention maycomprise, essentially, a compartment provided with means for maintaining a body of liquid therein, a looped carrier element having a plurality of agitator and elevator elements secured thereto, and having its lower portion mounted for move- 5 ment through said body of fluid to subject the material therein to agitation and to scoop up and elevate or lift the coarser fraction of said material and discharge the same from the liquid body separate from the finer material in suspension 10 in said body, and agitating means adapted to effect an aerating agitation of said liquidbody at a point removed from said carrier element. The apparatus is also provided with separate launder means for removal of a froth flotation l5 concentrate and for removal of liquid containing suspended slimes. Numerous modications of the apparatus may be made according to the principles herein set forth. examples of which are shown in the attached drawings, and refer- 20 ring thereto: y

Fig. 1 is a partly broken away plan view of one form of my concentrating apparatus;

Fig. 2 is a partly broken away side elevation thereof Fig. 3 is a vertical section thereof taken online k3---3 in Fig. 2;

Fig. 4 is an enlarged scale detail of one of 'the agitator or elevator elements which may be provided according to my invention; 30 y Fig. 5 is a view corresponding to Fig. 3, showing a modified form of apparatus of the general type shown in Figs. 1 to 3;

Fig. 6 is a transverse section of a modied form of apparatus embodying an elevator classi- 35 fier and flotation means, taken on line 6-6 in Fig. 8:

Fig. '7 is a-transverse sectional view of the apparatus taken on line 1-1 in Fig. 6;

Fig. 8 is a horizontal section of the device o taken on line 8-8 in Fig. 6; y

Fig. 9 is a plan view of another modified form of the invention, the upper portion of the elevator being broken away;

Fig. 10 is a section on line IU-IU in Fig. 9; 45 and Fig. 11 is a section on line II-II in Fig. 9. f

Referring to Figs. 1 toi3, the device may comprise a tank I provided with a curved bottom wall 2 and end walls 3. The tank l may be of 50 substantially any desired shape, but in 'view of the fact that the present described form of invention provides two adjacent elevator elements, the aforesaid tankis preferably of a rectangular shape. Above the tank I I preferably provide a housing 4 within which the elevator classifier assembly may be disposed, said assembly comprising a pair of headpulleys 5 mounted on a shaft 6 provided with suitable driving means such as a gear train 'I and each of said pulleys carrying an endless flexible carrier member 8 provided with a plurality of elevator elements or buckets 8, and looped downwardly from said head pulleys below the level of liquid in said tank, as hereafter more fully described. Any desired number of pulleys 5 andcarriers 8 may be provided, said pulleys being preferably mounted on a common shaft, depending upon the classifying capacity desired in' the apparatus.

As shown in Fig. 4, the buckets 8 may be formed f as a bent plate defining an open-ended bucket with the flexible carrier 8 and secured thereto in any suitable manner as through the agency of rivets II which are preferably located medially along the height of that portion of the plate which backs against the carrier 8, whereby proper flexure of the carrier member 8 may -be obtained at the position of the head pulley. The carriers 8 are moved in the direction indicatedby the arrow in Fig. 3 upon clock-wise rotation of the pulleys 5 through the agency of the aforesaid gear train, and the buckets 8 are so arranged on said carriers that the crotches, I2 thereof are directed upwardly along the ascending run of said carriers. 2

The tank I is provided with slimes overflow means which, in this embodiment, may comprise an overflow launder I3 extending longitudinally of said tank in the center of an inner zone I deflned by the lower portion I4 of the downwardly looped portion of the carriers 8 and extending in the direction of the axis of rotation of the head pulleys 5, the. lips of said overow launder defining a pulp or liquid level within the tank I as indicated by the dash line L. The housing 4 is preferably extended below the level L as at 4', and between said downwardly extending portions 4' and the longitudinal or side wall .portions I5 of the bottom 2 a suitable aerating agitating means-is preferably provided, such as a plurality of drop pipes I6 connected to an air header I1 through which a suitable quantity of air may be delivered to cause formation of a mineral-.bearingrfroth in accordance with conventional froth otatlon practice. Suitable baffles are preferably provided within the outer zone O which is defined by the side walls I5 of the tank I and the portion I4 of the carrier 8, constituting, in this embodiment, flotation zones at each side of the tank extending parallel to the inner zone I. Such baffles are shown at I8 and I9, and concentrate launders 2| are provided along said side wall portions I5 at a level somewhat above the level L aforesaid, in position to withdraw the produced froth according to. common practice.

Suitable means are provided for admitting a pulp containing the comminuted ore or other material to be treated, such as feed launders 22 which may communicate with the tank Iy at the aforesaid dotation zones at any desired position, for example, adjacent one end of said tank. 'I'he feed launders 22 preferably enter the tank I at a point below the level L. i

In the operation of the-present described form of the device, a suitable feed of comminuted ore in suspension in water or vother suitable fluid is introduced to the` tank I through the launders 22 (the tank I having been previously filled with water to the level L and a suitable flow of air through the drop pipes' I6-having been established), and the aerating agitation produced by the admission of air at I6 will result in the formation of a froth concentrate at the upper portion of the notation zones, it being appreciated that the feed will contain a desired quantity of flotation reagent according t'o common practice. It is well known that at a given rate of agitation with a proper proportion of flotation reagent, mineral particles of a certain size range will be caused to enter the froth and recovered as a concentrate, while particles larger than such size range will not be efficiently collected. Similarly, particles which are smaller than the aforesaid size range will be diicultly collected. For this reason the device of the present invention is highly adapted for efcient metallurgical performance if the feed is not ground too finely at first and is introduced in relatively coarse condition to the flotation zones, the particles which will fioat recovered in the concentrate, the unoated particles being then subjected to the classifying operation provided by the 'flexible carriers 8 and buckets 8 and passed to a further comminuting operation, and the fines, which generally contain no significant proportion of unrecovered values, allowed to escape continuously from the device at slimes overflow launder I3. The oversize particles or sands settle downwardly from the flotation zones and are picked up by the open-ended buckets 8 and carried over the pulleys 5, and suitable water supply means are preferably provided on the downward side of the pulleys 5 to assist in ejection of the collected sands from the bucket crotches I2. Such water supply means may comprise a plurality of valved nozzles 23, positioned to forcev jets 24 of water against l the moving buckets 8, which water, together with the ejected sands, fiows downwardly into a sands launder 25 provided along one side of the device adjacent the `upper end of the housing 4. A suitable sheet metal cover or the like may be provided as at 26 to enclose the head end of the device, if desired. 'I'he slimes are carried away from the pulp body in suspension at the slimes overflow launder I3', which, in this.embodment, is disposed ln the relatively quiescent inner zone I, thus affording maximum opportunity for the coarse particlesv to settle into position to be scooped up by the buckets 8.'

The form of apparatus shown in Fig. 5 conforms in general to that shown in Figs. 1 to 3, differing principally with respect to the position of the flotation zone with respect to the classifier structure. Referring thereto, a tank 21 is provided with a'curved bottom `28 and a housing 28 extending upwardly from said tank in a manner comparable to the housing 4 above, carrying a pulley 5 mounted on a shaft 6. -The pulley 6 carries a flexible carrier 8 provided with bucketsl 8 after the manner above described, which'carrier loops downwardly within the tank 21 to a point adjacent the curved bottom 26.' The aerating agitator structure is disposed within the inner zone I defined by the looped portion 30 of the carrier 8 and may comprise an air header 3I provided with a plurality of drop pipes 32, suitable bames being provided as at 33 to properly direct the flow of the froth and breakup the froth bubbles formed by admission of air at 32. A baille 34 is preferably provided at one side of the iiotation zone to minimize travel of froth outside of. the flotation zone and a concentrate launder is provided at 35 for withdrawal of concentrate from said zone. Sllmes overflow launders 36 may be provided along the edges of the tank 2'I and a suitable sands launder may be provided as at 31 in accordance with the showing at 25 above, suitable water jet means being provided as at 38. A sheet metal cover 39 over the head end of the carrier member may also be provided, if desired. `It Will be understoodthat any suitable number of pulleys 5 and carrier members 8 may be provided.

The operation of this form of the invention is quite comparable to that described in connection with the showing in Figs. 1 t-o 3, a suitable feed being introduced through a feed launder which may open into the otation zone as at 40, flotation effected by admission of air through the pipes 32, and the froth concentrate withdrawn at 35. The unfloated heavy particles pass exterior of the flotation zone at the sides of the carrier 8 into the outer zone O', the oversize sands being re-v prising a tank orl boot 4I which may be formed with upwardly flaring side walls 42 and may, for example, be square or rectangular'in shape. In this form of the device, provision is made for withdrawing the overfiow of classified slimes alongtwo opposite sides of the device as at 43 and 44 and for withdrawing froth from the device at the remaining sides as at 45 and 46, as will be more fully described subsequently. The classifying elevator means extends within the boot 4I and may consist of a belt or fiexible member 41 mounted on a. drum or pulley 48 carried by a shaft 49 which is ,journaled in suitable bearings 5| suitably mounted on a casing 52 which is in turn mounted on or within the tank or boot 4I. 'Ihe belt 41 is provided with open-ended buckets or lifts 53 secured thereto and adapted to operate as agitating and elevating means. The shaft 49 may be driven by any suitable means so as tocause a movement of the belt 41 in the direction indicated by the arrow A. An idler roll or drum 54 may be mounted on the elvatorbelt 41 at the lower end thereof so as to hold the belt distended at proper curvature and to also hold the belt in substantially vertical position by its weight and prevent lateral deection by the reaction of the operation of the belt and buckets on the material in the tank. In most cases, however, this idler may be dispensed with, the weight of the buckets on the belt being sulcient to keep saidrbelt in proper position.

'Ihe buckets or lifts 53 may be of any suitable size and shape and are preferably formed as a blade or plate extending at an inclination to the elevator belt-and secured thereto in any suitable manner as by riveting. The inclination of the plates or buckets is upward and outward on the ascending run of the belt and downward and outward on the descending run of the belt, the buckets being open at each end so as to permit fines to drain from the buckets as the latter ascend from the body of pulp or fiuid undergoing treatment. A feed launder or chute 55 is provided for supplying pulp or material to be treated, discharging for example,iinto the interior of the casing 52 above the level of liquid in the tank 4I but sufficiently far from the elevator classifier means to enable the material so supplied to effectively gravitate or settle toward the bottom of the tank. The casing 52 is preferably not carried downwardly to the bottom of the tank 4 l but terminates as at 56 a short distance below the pulp level which is maintained by the overfiow lips 51 along the classifier overfiow launders 43 and 44, providing openings below the bottom of the casing to enable the coarser material in the pulp to settle to the bottom of the tank, directly below the elevator classifier and to also enable the finer material to pass outwardly and upwardly to the overfiow lips 51. At the upper portion of the casing 52 and on the side thereof which is adjacent the descending run of the eleyvator classifier, a launder or chute 56 is provided for receiving coarse material from the elevator classifier buckets and conveying the same to any suitable receiving means, to a ball mill or the like, and a defiector or inclined apron 58 is provided adjacent the elevator buckets to guide material discharged from said buckets inlto said launder 58, in` connection wherewith suitable water jet means may be provided as at 6| to facilitate complete discharge of material from the buckets.

Within the casing 52, along the axial ends or edges of the belt 41, I provide a distributing plate 62 disposed at an angle to the horizontal, at a level upwardly removed from the pulp level above defined. These baffles are preferably wider at their high side than at their low side and serve to interrupt the free fall of fluid or pulp discharged from the open buckets and distribute the same over the width of the casing v52, such liquid or pulp falling downwardly into the main body of pulp and resulting in the formation of a froth, which flows under suitable bailies 63 disposed parallel to the concentrate launders 45 and 46, which baffles may be formed as continuations of the sides of the casing 52 as in the manner shown at 56. These baffles preferably do not extend to as low a level within the bottom or' tank 4| as do the baffles 56, whereby the froth produced in falling from thebuckets will preferentially escape under the baffles 63 and thence to the concentrate launders 45 and 46, rather than under the baffles 55 and thence to the classifier launders 43 and 44.

The blades or buckets 53 function in a manner somewhat similar to the blades 9 above. The cascading action of the uid discharged from the open bucket ends is productive of the desired aeration, and the distributing baffles or plates 62 are placed at such height above the lfiuid level as to intercept an adequate quantity of material so discharged, and to. further aerate while distributing the same laterally with respect to the width of the tank 4|, whereby a substantially uniform supply of highly aerated froth is directed to the launders 45 and 46. Further" more, the descending run of buckets serves to 1= cnt-rain air pon entering the fluid body and to distribute th'e same `into said liquid body, while the lower end of the carrier belt 41 serves to adequately agitato the liquid within said tank.

The form of Athe invention shown in Figs. 9 to 11 comprises a tank 1I which may be rectangular with sloping side walls as shown, said tank having classifier overflow launders 12 extending adjacent the upper edges or lip 13 at two sides thereof and fiotation concentrator overfiow launders 14 extending adjacent the upper classifying elevator 18 consisting, for example, of a belt 19 running over a driving pulley 8l and provided with inclined buckets 82, suitable discharging means indicated at 83 being provided for receiving material discharged by gravity from the buckets after they pass over the drum at the upper end of the belt. Water jet means 83 are preferably also provided at the head end of the elevator mechanism to assist in the discharge 'of coarse material from the buckets 82 into discharging means 83. The lower ends of the walls of casing 11 extending down into the tank constitute baiiies, the baille portions 84 Which are between the belt 19 and the classifying overflow lips 13 extending to a lower level than the baffle portions 85 extending between the belt and the froth overflow lips 15.

In order to increase the flotation action of the apparatus, an auxiliary belt or movable member 86 is provided, for example, within the classifier belt and carried by a pulley 81, said belt being provided with blades 88 adapted to dip into the upper portion of the body of liquid or pulp in the tank and to produce a frothing action as hereinafter described. Driving means indicated at 89 and 9| are provided for the respective belts 19 and 86, said driving means being adapted to drive the frothing belt 86 at a much higher speed than the classifying belt 19.

In the operation of this form of the invention the pulp, which is assumed to contain some frethiiig agent, is supplied to the tank through the feed chute 16 and the coarser material settles to the bottom of the tank and is eventually elevated by the classifying elevator belt 19 and discharged at 83. The notation belt 86 is operated at suiiicient speed to pick up the pulp from the upper portion of the body of liquid in the tank and to carry such pulp over the top of the belt and cause it to cascade into the body of liquid at the descending side of the belt, producing a very effective frothing action. This cascading takes place both from the ends and the outside edges of the flotation belt and results in production of a body of froth which flows under the lower edge or-` baille portion 85 of the vertical casing 11 and over the froth overflow lip indicated at 15 into the froth overflow launders 14 at each end of the tank, the bailles 84 extending below the level of the layer of froth so as.to prevent the froth from passing to the classifier overflow launders 12 and directing all the froth into the concentrate launders 14. The fines from the pulp overow into launders 12, so that the operation of this apparatus effects separate recovery of the flotation concentrates, the fines or slimes, and the coarse material for regrinding. 'I'he apparatus may be applied to treatment of mineral-bearing pulp containing residual frothing agent as a result of previous flotation operations, or it may be applied to the treatment of fresh pulp together with added frothing or flotation agent.

I am aware of the fact that previously described forms of flotation apparatus'have been provided with aeration means such as paddlelike beaters in position to act upon the pulp and mechanically or physically inject the pulp into the produced froth. 'I'he present-described apparatus functions on a materially different principle, in that the pulp is elevated from the main pulp body and allowed to cascade to the upper surface of the pulp body, which cascading causes an aeration of the cascaded portions and an entrainment of air by the particles as they enter the pulp body in a manner which is not possible with the beater-type apparatus above referred to. Furthermore, the presence of the flexible carrier, with, its agitator and elevator elements, within the main Vbody of pulp provides a constant agitation of the pulp under conditions of at least partial aeration of such pulp body.

It will be seen that each of the forms of apparatus above described serves to separate a otation concentrate, a-slimes product, and a coarse product. Each of these products is separately discharged and may be delivered to any suitable point for further treatment or disposition. In general, the slimes product may be discharged to waste, while the coarse product is preferably returned for further comminution, after which it may be subjected to a further concentration, either in another apparatus or by returning it to the same concentrating'apparatus in closed circuit with the grinding mill or other comminuting apparatus.

.Other modifications of the device, for use either as a flotation apparatus or as a simple agitating apparatus, will occur to those skilled in the art, and I in no wise choose to be limited to the specific structures disclosed, but rather to the scope of the appended claims. For example, I may employ one or more chains supported by suitable sprockets mounted on the shaft 6 in Figs. l to 3 instead of the belt 8, the blades 9 being secured to the chains in any suitable man-l 4particular type of flexible carrier employed, a

pulley for a belt, a sprocket wheel for a chain, a grooved pulley for a cable, and the like. Other forms of elevator buckets may also be employed, as shown for example in my above-mentioned copending application Ser. No. 15,041.

I claim:

l. A concentrator whichl comprises: a tank provided with means for supplying thereto a pulp containing divided material together withliquid -and with froth flotation agent; movable elevator means extending into said tank and comprising an endless flexible carrier hfaving its upper end mounted above said tank on a rotatable supporting means to provide a downwardly looped portion extending within said tank, said looped portion having ascending and descendingrun portions, and a plurality of open-ended bucket means secured to said flexible carrier, said bucket means being directed upwardly and downwardly respectively-on said ascending and descending run portions and adapted to agitate the material in said tank and to scoop up coarse material and lift the same from said tank while allowing liquid to drain therefrom through the open ends thereof and to discharge such coarse material outside of said tank, said downwardly looped portion of said carrier defining with said tank an inner zone and an outer zone extending parallel to the axis of 'rotation of said supporting means; driving means for said rotatable supporting means; slimes overflow means in one of said zones for maintaining a liquid level in said tank; froth producing means in the other of said `zones for producing a froth concentration in said zone; and concentrate overflow means in said other zone for withdrawing the froth so produced.

2. 'Ihe apparatus set forth in claim 1, said one zone comprising said inner Zone.

3. The apparatus set forth in claim 1, said one zone comprising said outer Zone.

4. A concentrator which comprises: a tank provided with means for supplying thereto a pulp containing divided material together with liquid and with froth flotation agent; movable elevator means extending into said tank and comprising an endless flexible carrier having its upper end mounted above .said tank on a rotatable supporting means to provide a downwardly looped portion extending within said tank, said looped portion having ascending and descending run portions, and a plurality of openended bucket means secured to said flexible carrier, said bucket means being directed upwardly and downwardly respectively on said ascending and descending run portions and adapted to agitate the material in said tank and to scoop up coarse material and lift the same from said tank while allowing liquid to drain therefrom through the open ends thereof and to discharge such coarse material outside of said tank, said downwardly looped portions of said carrier defining with said tank an inner Zone and an outer zone extending parallel to the axis of rotation of said supporting means; driving means for said rotatable supporting means; slimes overflow means in one of said zones for maintaining a liquid level in said tank; air-admitting means in the other of said Zones for admitting air into said zone below said liquid level to produce a froth concentration in said zone; and concentrate overflow means in said other zone for withdrawing the froth so produced.

5. The apparatus set forth in claim 4, said one zone comprising said inner zone.

6. The apparatus set forth in claim 4, said one zone comprising said outer zone.

7. A concentrator which comprises: a tank provided with means for supplying thereto a pulp containing divided material together with liquid and with froth il `Itation agent; movable elevator means extending into said tank and comprising an endless flexible carrier having its upper end mounted above said tank on a rotatable supporting means to provide a downwardly looped portion extending within said tank, said looped portion having ascending and descending run portions, and a plurality of open-ended bucket means secured to said flexible carrier, said bucket means being directed upwardly and downwardly respectively, on said ascending and descending run portions and adapted to agitate the material in said tank and to scoop up coarse material and lift the same from said tank while a1- lowing liquid to drain therefrom through the open ends thereof and to discharge such coarse material outside of said tank, said downwardly looped portions of said carrier defining with said tank an inner zone and an outer zone extending parallel to the axis of rotation of said sup porting means; driving means for said rotatable supporting means; slimes overflow means in said outer zone for maintaining a liquid level in said tank; mechanical agitating means in said inner zone adjacent and extending below said liquid level; means for operating said mechani cal agitating means to produce a froth concentration in said zone; and concentrate overflow means in said inner zone for withdrawing the froth so produced.

ALEXANDER C. MUNRO.n 

